Bitcoin transactions and its emission are regulated by an extensive peer-to-peer network. Bitcoin uses a distributed public universal database spread through a decentralized peer-to-peer network that uses digital signatures and is supported by a proof-of-work protocol to ensure security and legitimacy of funds in use.

To guarantee that a third-party, let's call her Eve, cannot spend other people's bitcoins by creating transactions in their names, Bitcoin uses public key cryptography to make and verify digital signatures. In this system, each person, such as Alice or Bob, has one or more addresses each with an associated pair of public and private keys that they may hold in a wallet. Only the user with the private key can sign a transaction to give some of their bitcoins to somebody else, but anyone can validate the signature using that user’s public ke

Bitcoin is the most widespread cryptocurrency. Its total market value is over $171 billion. One can exchange, buy or sell Bitcoins on many sites.
Despite the fact that using Bitcoin does not formally require user identification, the currency is not completely anonymous.

Blockchain — is a continuously growing list of records, called blocks, which are linked and secured using cryptography. Each block typically contains a hash pointer as a link to a previous block, a timestamp and transaction data. By design, blockchains are inherently resistant to modification of the data. For use as a distributed ledger, a blockchain is typically managed by a peer-to-peer network collectively adhering to a protocol for validating new blocks. Once recorded, the data in any given block cannot be altered retroactively without the alteration of all subsequent blocks, which requires collusion of the network majority.

Blockchains are secure by design and are an example of a distributed computing system with high Byzantine fault tolerance. Decentralized consensus has therefore been achieved with a blockchain. This makes blockchains potentially suitable for the recording of events, medical records, and other records management activities, such as identity management, transaction processing, documenting provenance, or food traceability.

The first blockchain was conceptualised in 2008 by an anonymous person or group known as Satoshi Nakamoto and implemented in 2009 as a core component of bitcoin where it serves as the public ledger for all transactions. The invention of the blockchain for bitcoin made it the first digital currency to solve the double spending problem without the need of a trusted authority or central server. The block chain is the main innovation of Bitcoin.

Mining is the process of adding transaction records to Bitcoin's public ledger of past transactions (and a "mining rig" is a colloquial metaphor for a single computer system that performs the necessary computations for "mining"). This ledger of past transactions is called the blockchain as it is a chain of blocks. The blockchain serves to confirm transactions to the rest of the network as having taken place. Bitcoinnodes use the blockchain to distinguish legitimate Bitcoin transactions from attempts to re-spend coins that have already been spent elsewhere.

Bitcoins, issued with the help of mining are the best way to hold the transaction anonymity during the work with cryptocurrency. Nevertheless, they can be used only after getting 100 network confirmations.

Bitcoin mining is so called because it resembles the mining of other commodities: it requires exertion and it slowly makes new currency available at a rate that resembles the rate at which commodities like gold are mined from the ground.

Initial coin offering (ICO – is an initial coin offering, an unregulated crowdfunding tool using cryptocurrencies, which can be a source of funding for startups.

When a developer of cryptocurrency wants to raise funds through the ICO, it publishes a detailed actions plan. This plan describes what kind of project it is, what needs it solves, how much money you need to start it up, how much its own cryptocurrency (tokens) will be issued, what share of it will be sold, ICO campaign terms and other technical details.

Funds are raised on special platforms using the blockchain technology. Therefore, all transactions are protected by cryptography and are anonymous.

If the required amount can not be raised within the prescribed period, ICO is recognized as failed, and all money is returned to investors. If the campaign is successful, this money is used to finance the project.

Cryptocurrency — is a type of digital currency, the issuing and accounting of which are based on cryptographic methods, for example, the Proof-of-work protection method and asymmetric encryption, and the system functions decentrally in a distributed computer network.

In case of cryptocurrency it is impossible to cancel or return the funds sent to the recipient, but there are opportunities for transactions involving the intermediary, when the consent of all three or any two parties is required to complete or cancel the transaction, the funds cannot be forcibly frozen or recovered without access to the owner's private key, although the parties of the transaction may voluntarily temporarily block their funds as collateral.

All currently existing cryptocurrencies are used pseudonymously - all transactions are public, but there is no default binding to a particular person, although the user's identity can be established if the necessary additional information is known.

Cryptocurrency market – is a complex of all existing cryptocurrencies and the infrastructure that provides them. Capitalization of the cryptocurrency market The exchange rate of the currency is very volatile, so the capitalization of the cryptocurrency market is constantly changing, but the long-term trend is rising.

As of November 20, 2017, the total capitalization of the market was $ 243 billion, with more than half ($ 136.9 billion) accounted for by bitcoin, the exchange rate of which on this date exceeded $ 8200 for the first time. For comparison, the total capitalization of the cryptocurrency market in March 2017 was only $ 25 billion.

Among the cryptocurrencies that have shown great growth recently (as of the end of November 2017) Bitcoin Cash, which displace Ethereum from the second place by the price of one coin and as of 23.11.2017 it costs $ 1319.484 with a capitalization of $ 22.147 billion.